The storied Jewish-American publication is suspending its print operations and plans to lay off about 40 percent of its editorial staff — including editor-in-chief Jane Eisner — while moving to digital-only.

A print publication for 121 years, The Forward will continue to produce an English-language and a Yiddish-language edition online.

“The Forward is taking the next step in making our brand more relevant to our readers and more connected to their lives,” said publisher and CEO Rachel Fishman Feddersen.

“We are announcing that this spring The Forward will complete its evolution from what was once a print-focused publisher to become a digitally focused publication.”

The Forward is eyeing growth among its under-35 readers who prefer to read news online. Currently that segment amounts to a third of total readers.

“It’s a sad day for the publication,” said one laid-off staffer who requested anonymity. “Hopefully, they can turn it around.”

“The revenue is not really there,” said a source. “They’ve been losing money for years but lately the losses have been more than $5 million a year.”

The publication is owned by The Forward Association, a not-for-profit whose endowment swelled to more than $100 million when the association sold its former headquarters on the Lower East Side as well as the radio station WEVD.